The present disclosure relates generally to the field of airbag use in motor vehicles. More specifically, this disclosure relates to a multiple chamber airbag having different pressures in each chamber to optimize restraint forces on the occupant to mitigate occupant injury.
Airbags are located in vehicles to protect occupants from injury during a vehicle dynamic impact event, which triggers sensors located in the vehicle to initiate deployment of an airbag(s). An airbag may deploy and inflate, by gas rapidly-entering its cushion(s) or chamber(s), typically through the use of an inflator containing an explosive charge (e.g., pyrotechnic device). Passenger airbags are typically stored within and deployed from the passenger dashboard compartment, and are typically packaged through a process of folding and rolling to compact the airbag in order to minimize its required packaging space. During a vehicle dynamic impact event, a passenger airbag deploys, typically from the upper portion (i.e., above the glove box) of the dashboard, in substantially rearward and upward directions to protect the head and torso of the occupant.
It has been known to construct a vehicle to include a passenger airbag 60 which may be mounted on the top facing surface of the dashboard, as shown in FIG. 3, or on the rear facing surface of the dashboard, as shown in FIG. 4. The airbag 60 may be constructed having a single chamber whereby the gas generated by the inflator is directly forced into the airbag chamber, unfolding and expanding the airbag chamber to provide protection to the vehicle occupant during a vehicle impact. It has also been known to construct a bi-lobular airbag, which includes a single chamber airbag having two adjacent lobes separated by a gap or void, whereby each lobe is directly inflated by the inflator. These methods of construction have several disadvantages, the key disadvantage being that during deployment of the airbag, each chamber or lobe will have substantially similar expansion forces, therefore exerting substantially uniform restraint forces onto all areas of contact with the occupant.
It would be advantageous for an airbag to be constructed to include of multiple chambers, whereby each chamber may exert a different predetermined restraint force onto the occupant, thereby mitigating occupant injury by optimizing restraint forces (i.e., having lower restraint forces on the lower mass head and neck regions, while having higher restraint forces on the higher mass chest or torso region). This configuration would provide optimized occupant protection and reduce head and neck injuries.